Farmers' leaders are urging European Union decision-makers to extend the free-range status of poultry which had to be brought indoors following an outbreak of bird flu, warning some might otherwise go out of business.

The UK government's chief vet declared a 'prevention zone' in England on December 6, and ordered all keepers of poultry and captive birds to implement measures to protect birds against H5N8, a form of avian influenza currently circulating in Europe.

It required commercial and individual poultry and captive bird keepers to keep their birds inside, or take steps to separate them from wild birds, and was later extended.

Free range producers can still continue to market as free range produce, provided the order does not extend beyond 12 weeks.

The UK farming union presidents will hold urgent discussions with MEPs and European Union (EU) decision-makers, urging them to extend the 12-week free-range status of poultry affected by the compulsory housing order that is in place until February 28, when the 12 week limit expires.

They want the extension to apply to free range eggs and poultry meat and continue until the risk from bird flu subsides.

'We are in uncharted territory and this situation requires new measures that will help to solve the concerns of producers,' the presidents said in a joint statement.

'The UK market will, without doubt, be one of the most affected countries as a result of bird flu, due to half of our national flock being free-range, by far the highest percentage of any member state.

'If these steps aren't taken to protect the industry, producers are facing the very real prospect that they could go out of business and the UK market will be unable to enjoy the free-range products they demand.'

British farmers had been quick to introduce enhanced biosecurity measures and made sure welfare remained an absolute priority, they said.

Eight cases of the disease has been found in domestic poultry flocks.

European farmers' organisation Copa-Cogeca, has written to the European Commission setting out the concerns of European farmers and offered possible solutions ahead of a meeting with MEPs.